[Thread] Filter Out Emails in `Trash/Drafts/Templates` from Thread View

[dab246]

Related

• ADR-0072
• PR #4380 comment from @Crash--

Description

A thread can contain emails spread across multiple mailboxes. Emails belonging to Trash, Drafts, or Templates should not appear in the thread view and should be excluded from thread-aware actions.

Rationale

• Trash: user already deleted the email — it should not reappear in thread view
• Drafts: not yet sent — should not be shown as part of the conversation
• Templates: not a real email in the conversation

Tasks

• After ThreadExpansionService.expandThreads() returns, filter out emails whose mailboxIds contain Trash, Drafts, or Templates mailbox IDs
• Resolve Trash/Drafts/Templates mailbox IDs from MailboxDashboardController or session capabilities
• Apply the filter to both:
  • Thread detail view (displaying emails within a thread)
  • Thread-aware actions (do not perform actions on filtered-out emails)
• Handle edge case: if all emails in a thread are filtered out, hide the thread from the list or handle gracefully

Acceptance Criteria

• Emails in Trash do not appear in thread view
• Emails in Drafts do not appear in thread view
• Emails in Templates do not appear in thread view
• Thread actions only apply to non-filtered emails
• A thread containing only filtered emails is hidden or handled gracefully

[coderabbitai]

🔗 Related PRs

#4255 - Fix email content not displayed on Tablet when enabling thread view [merged]
#4316 - TF-4314 Fix unread emails disappear blink [merged]
#4340 - TF-4336 Fix INBOX should be above Favorite folder [merged]
#4372 - TF-4368 Fix cannot scroll in email list [merged]
#4377 - TF-4373 Fix deletion is not working on thread [merged]

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